Constipation after surgery is VERY common, and the main cause is usually the strong painkillers. Opioids, the morphine-type painkillers often given after orthopedic surgery, slow your gut right down. Somewhere between 4 and 9 in 10 people who take them get constipated.
The fix is to start EARLY. Drink steadily, walk little and often, eat fiber from food, and ask about a laxative at the same time you start the painkillers, rather than waiting until you’re blocked up.
Most people get going again within a few days. If you’ve gone several days with nothing and your belly is swollen, painful or you’re being sick, that needs a call today.
Why surgery makes you constipated
- Opioid painkillers: they slow the muscle waves that push food through your gut, so more water is drawn out and the stool turns hard and dry. They also tighten the muscle at your back passage. This side effect often doesn’t fade the way the drowsiness does
- The anesthetic: general anesthesia and some of the other medicines used during surgery slow the bowel for a while afterward
- Moving less: your gut gets lazier when you do. After hip, knee or spine surgery you spend far more time sitting and lying
- Eating and drinking less: fasting before surgery, a poor appetite, nausea, and drinking less so you don’t have to get up to the toilet so often
- Other medicines: some, such as iron tablets for a low blood count, can add to the problem
- Toilet trouble: a low toilet, a strange bathroom, no privacy, or fear of straining on a sore wound or back. Putting off the urge makes stool harder to pass
How to prevent it
- Have a plan before you need it. If you go home with opioids, ask your doctor or pharmacist what to take for your bowels at the same time. It’s far easier to prevent constipation than to clear it
- Drink steadily through the day. Water is best. Pale yellow urine is a good guide. If you’ve been told to limit fluids for heart or kidney reasons, follow that advice
- Walk little and often. Short walks every hour or two while you’re awake help your bowels and your circulation. See blood clots after surgery
- Eat fiber from food. Fruit, vegetables, oats, whole grains and beans. Build up gradually so you don’t bloat
- Go when you feel the urge. Don’t hold it in. The gut often wakes up after meals, especially breakfast, so give yourself unhurried time then
- Cut down the opioids as soon as you can. As the pain settles, follow your team’s plan for moving to simpler painkillers. Less opioid means less constipation. See knee replacement recovery week by week for how pain usually changes
Don’t wait until you’re blocked. Start the bowel plan the same day you start the painkillers.
Using the toilet after hip, knee or back surgery
- Knees above hips: a small footstool under your feet makes it easier to go. After a hip replacement, check first. If you’ve been told not to bend your hip too far, a raised toilet seat may come first and a footstool may not suit you. See hip replacement precautions
- Breathe, don’t strain: relax your belly and breathe out slowly as you push. Hard straining hurts wounds and sore backs
- Support what’s sore: after back surgery, a cushion hugged against your belly can make it feel safer to push gently
Laxatives: the main types
Laxatives are often needed while you’re taking opioids, and for most people they’re fine for short-term use. The main types work in different ways:
- Stool softeners: let more water into the stool so it’s softer. Gentle, but on their own they often aren’t enough against opioids
- Osmotic laxatives: hold water in the bowel so the stool stays soft and easier to pass. They can take a day or more to work
- Stimulant laxatives: make the bowel muscles push. They often work overnight and can cause cramping
- Fiber supplements: usually not the first choice while you’re on opioids. They add bulk that a slowed gut struggles to move, especially if you’re not drinking much
- Suppositories and enemas: work directly in the back passage when stool is stuck low down. These are usually a later step
Which one suits you depends on your other medicines, your heart and kidney health, and how blocked you are. Ask your pharmacist or doctor which type to use and how much, and stop once you’re back to normal and off the opioids. MedlinePlus has a clear guide to constipation self-care.
What’s normal
- Nothing for the first day or two after surgery is common, especially if you’ve eaten very little
- Wind and mild bloating as your gut wakes up
- A hard, uncomfortable first bowel movement. It usually gets easier after that
- Taking a couple of weeks to feel regular again while you cut down the painkillers and move more
Go to the emergency department if
- You haven’t had a bowel movement or passed wind for several days, and your belly is swollen or hard and you’re vomiting
- You have severe or worsening belly pain
- You pass a lot of blood from your back passage, or black, tarry stools
- After back surgery, you have new numbness between your legs or lose control of your bladder or bowels
Call your surgeon or doctor today if
- You’ve had no bowel movement for 3 days or more despite laxatives
- Your belly is bloated and sore, or you feel sick
- You’re leaking watery stool after days of constipation. This can mean hard stool is stuck higher up
Get it checked if
- You see small streaks of bright red blood on the paper
- Constipation is still a problem after you’ve stopped the opioids
- Your bowel habits have changed and haven’t settled
The painkillers slow your gut down. Water, walking and an early plan get it moving again.